<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title></title>
    <style>
        .all {
            display: flex;
        }

        * {
            padding: 0;
            margin: 0;
        }

        .menu {
            width: 120px;
            background-color: red;
            position: relative;
            height: 26px;
        }

        .menu .sub {
            position: absolute;
            display: none;
            left: 0px;
            top: 26px;
            background-color: gray;
            width: 100%;
        }
    </style>
    <script src="https://code.jquery.com/jquery-3.6.0.js"></script>
    <script>
        $(function () {
            $('.menu').mouseover(function (e) {
                $(this).find('.sub').toggle();
            });
            $('.menu').mouseout(function (e) {
                $(this).find('.sub').toggle();
            });
        });
    </script>
</head>

<body>
    <div class="all">
        <div class="menu"><span>微博</span></div>
        <div class="menu"><span>微博</span></div>
        <div class="menu"><span>微博</span></div>
        <div class="menu">
            <span>微博</span>
            <dl class="sub">
                <dd><a href="">私信</a></dd>
                <dd><a href="">评论</a></dd>
                <dd><a href="">@我</a></dd>
            </dl>
        </div>
    </div>
</body>

</html>